#include <stdio.h> 
int main()
{
	int n = 0;
	float sum = 0;
	int age = 0;
	scanf("%d", &n);
	for ( int i = 0; i < n; i++ ) {
		scanf("%d", &age);
		sum += age;
	}
	printf("%.2f", sum/n);
	return 0;
}
